Volodi, I am not sure about how useful the POST initiative is for OpenACS as it in effect is for companies developing components using Java, and usable by vendors who deploy solutions integrating Java components. The component based approach is pretty common already (www.componentsource.com) where companies instead of developing software from the scratch integrate components that could be bought off the shelf. But it's pretty much within the .NET, Java lobbies....each with their own set of Lego blocks :)
Sun, Plumtree, Bea et al seem what you could say yay...Java lobby :). And, this just seems an initiative of theirs to definine a set of Java APIs for portal and portlet vendors who build their applications/portlets(as you see them). And they are supporting this with their resources. For example, even Microsoft does this by providing resources and standards for anyone to develop .NET components, that could be integrated into their supported portal frameworks.
In a way, incorrectly speaking, OpenACS has people developing new packages (kinda like components?...I am not sure it's the right comparison, anyone can correct me) and it does have guidelines for people who want to develop new package on how to do the same. Having said so, there are many standards and open initiatives that people in the community are looking at leaning towards. For example SCORM for all the learning stuff et al...